An assembly cell for performing automated assembly operations is provided. The assembly cell includes a fixed supporting structure defining an assembly station, a conveying device for feeding a work piece, such as a cylinder head, to the assembly station for the purpose of assembling thereon one or more accessory elements, and for sending the work piece out of the assembly station once the assembly operations are completed. The assembly cell also includes a means for referencing in position and supporting the work piece in the assembly station during execution of the assembly operations and a manipulator means moveably mounted to the supporting structure for execution of the assembly operations on the work piece present within the assembly station. The manipulator means are designed for simultaneous assembly of a plurality of elements on the work piece and are adjustable for varying the distance between the positions of the elements.
The assembly cell can be dedicated to the assembly of various parts, such as those of multi-cylinder internal combustion engines, wherein the manipulator means are designed for simultaneous assembly of elements associated to the different cylinders of the engine and are adjustable so as to be able to operate on components of engines having different values of the distance between the centres of the cylinders.
The assembly cell is capable of operating on a series of different types of work pieces, such as differently configured engines. This enables both adaptation of the cell for carrying out a given assembly operation, such as, for example, assembly of the engine valves on a new type of engine whenever it is decided to pass from the production of an old type of engine to the production of the new type, and adaptation of one and the same type of cell for automated assembly operations to provide different stations in an automated assembly line.
The manipulator means may comprise a plurality of gripping members supported by a structure that can be displaced in a controlled way according to a vertical axis and a horizontal axis orthogonal to the longitudinal direction of a line for conveying the pieces through the assembly cell. The gripping members are carried by the supporting structure so that the distance between the gripping members can be adjusted.
The means for position referencing and support of the work piece in the assembly station may include a device having means that enable orientation of the work piece via an oscillation about a horizontal axis parallel to the longitudinal direction of the line for conveying the work pieces through the assembly cell, as well as displacement of the work piece in the aforesaid longitudinal direction. Due to the combined movement of the means for supporting the work piece and the means for supporting the members for gripping the parts to be assembled, it is possible to pre-arrange the automated cell for carrying out assembly on work pieces, such as engines, having different geometries, for example, different values of the distance between centres of the cylinders, and presenting different positioning and orientation of the parts to be assembled on the work piece. For this purpose, the work piece, such as for example a cylinder head, is fed to the assembly station, being kept aligned in the longitudinal direction of conveyance, so that a variation of the distance between the gripping members can be used for adapting the cell to operating on engines having different distances between centres of the cylinders.
The principle described above with reference to the members for gripping parts to be assembled on the engine can also be applied, for example, where it is necessary to engage the piece that is in the assembly station at predetermined points, for example, by means of retention elements designed to prevent elements already provisionally assembled on the work piece from becoming misaligned before they are definitively fixed.